The world production of cellulose on land is 40 billion ton per year and the stock of cellulose is 700 billion ton.
The world consumption of fossil fuels is 8 billion ton per year.
The food production in the world is 3 billion ton per year.
From these 3 numbers we conclude that to take out from food, materials to produce bio ethanol or vegetable oils for biodiesel would not solve the problem of substituting fossil fuels, and would cause hunger.
On the other side, there are large surfaces of arable land, which are not cultivated or which produce plants not suitable for food. In these surfaces, the production of cellulose from trees or bush is possible. On the other side, cellulose containing biomass is a side product of many food crops.
One of the crops which produce large quantities of cellulose is sugar cane, which has an yield of 80 ton per hectar, In one ton of sugar cane there are about 80 kg of sugar, which may be converted to 50 kg of bioethanol. Besides sugar there are 250 kg of cellulose and hemicellulose, which is a much bigger quantity than sugar, which is not converted to liquid fuels. There are also about 80 kg lignin, which may become a useful energy source in the conversion of cellulose in liquid biofuels.
Cellulose, hemicellulose and starch have been studied in the past as possible sources of raw materials for liquid fuels and chemicals.
Wood itself is since thousands of years an energy source. Biomass is used today to produce electricity, but electricity represents only 10% of the consumption of fossil fuels. It is therefore important to find a process to convert cellulose in liquid fuels, suitable for energy supply to transportation and industry, which represent 90% of the consumption of fossil fuels.
The substitution of fossil fuels is also important because of the carbon dioxide which they produce by burning. Although cellulose also produces carbon dioxide by burning, the same quantity of carbon dioxide was taken out of the atmosphere by photosynthesis to produce cellulose.
Although the carbon dioxide content on earth was up to 6000 ppm 100 million years ago, it decreased to 250 ppm in the nineteen century and increased again up to 380 ppm. This sharp increase in the last century is caused by burning fossil fuels and causes dramatic climate changes due to the greenhouse effect.
As a consequence, to convert cellulose into a liquid fuel is since decades a challenge for scientists, because the existing cars and trucks could drive with such a liquid biofuel without major changes in the motor.
The exhausting oil reserves and the political dependence on unstable countries producing oil is also a major problem today.
Producing electricity from nuclear or from renewable sources like wind, waves, rivers or photovoltaic, is used today, but represents only 20-30% of electricity production. The rest is produced from fossil fuels.
The substitution of liquid fuels by electricity for transports creates a major problem of storage and transportation of electricity, which is technically possible, but far more expensive than the cellulose biofuels (Biocell).
Because cellulose is renewable, abundant and not producing carbon dioxide by burning if photosynthesis is considered, there has been recent scientific work on following subjects (Bibliography 1 to 13):                dissolution of cellulose in ionic liquids instead of traditional processes using water and organic solvents        hydrolysis of cellulose in ionic liquids        dehydration of fructose in ionic liquids to hydroxylmethyl furfural        hydrogenation in organic solvents of hydroxymethyl furfural to isomers of dimethyl tetrahydrofuran        isomerisation of glucose to fructose        